drm/i915/display/tgl: Use TGL DP tables for eDP ports without low power support

Reusing icl_get_combo_buf_trans() for eDP was causing the wrong table
being used when the eDP port don't support low power voltage swing table.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Cc: Lee Shawn C <shawn.c.lee@intel.com>
Cc: Khaled Almahallawy <khaled.almahallawy@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200826201549.83658-1-jose.souza@intel.com